Silverbulet

I took my 1996 F150 today to get an emissions test done. It failed because it would not set the drivability monitors. I had never heard of this. So the guy tells me to go drive it and bring it back. After a quick 15 to 20 mile ride I pulled back up and he plugs in his machine and says he thinks everything will be fine and it should pass. The minute I turn the ignition off....it cleared EVERYTHING AGAIN!! The truck drives fine and passes everything but the Drive Cycle Readiness Monitors. They clear when I shut off the ignition. Has anyone been through this? Can you tell me what to do. I do have a air bag light flashing a 51 code. However I was told that was not an issue.

tonyjklh

Its likely a bad fuse. The PCM has multiple power sources, key on power and all the time power. Just like your radio it needs constant power to maintain its memory, which includes the drive cycle monitor. So, the fuse for constant power may be blown which would mean it resets everytime you turn off the ignition. If that's not it then it may be a bad PCM.

Silverbulet

I have been told that about a fuse but where in the world would it be and what is it called?

Steve83

You don't need to start identical threads on the same BBS - one is enough.

You should NOT turn the engine off for a smog check - it puts the EEC back into open-loop for at least 3 minutes. Any smog tester should know that, and should NOT ask you to turn it off before the running tests. If he insists, ask to see the rules that require it. He probably misread them.

He also needs to follow special procedures for these early OBD-II vehicles - they don't work exactly the same as modern OBD-II, and they only have to pass the requirements for the year they were BUILT (not the year they're being tested) as it says clearly on the VECI label under the hood.


(phone app link)

It's his job to know how to do his job; it's not your job to teach him how to check your vehicle. If he doesn't know how, that DOESN'T mean your vehicle fails the test, or that you should pay more, or spend more time away from work.

Clearly, he saw that the readiness monitor was complete, and that it lost that status when the key was cycled. So he knows that it met the criteria for his test, and he caused it to restart the readiness monitor by telling you to turn the key off. I'd complain to his boss that he hasn't been adequately trained to test old vehicles (which are still legal to drive as long as they meet their build date's requirements).

Silverbulet

I didn't realize I posted double threads. I appreciate the information.

sdmartin65

Your 1996 is tested the same way any car 1996 and newer is tested. Part of this test is to verify the mil lamp is working, the only way to verify that is by turning the vehicle off.

I'm sure if you talk to the technician he would do the retest without shutting off the truck before hand. The problem you're having isn't very common but not unheard of so he might have ran into it before. Couple years of Dodge Stratus were notorious for doing the same thing.

Steve83

No, it's not. And even if it was, it could be done LAST, after all the other testing is complete.

sdmartin65

I figured you'd say that steve, but it's not helpful to answer on a topic you don't understand.

So OBD2 emission tests are fairly consistent from state to state. The test is computerized and will go through a list of emission devices the tech needs to verify as being present. The computer will also ask the tech if the mil light is working properly. Most times the problem will be a burnt out mil light. But all this data is entered prior to starting the test. The test sequence can't be altered by the tech, it's a computer program. But as I said before if you where to verify the mil with the tech, then go driving and come back for the retest he might agree to forgo checking the mil light again.

Steve83

IDK how many states you've lived in, or had vehicles smog-tested in, or worked in as a professional auto repair tech; but for me, it's more than 3. And their tests were not anywhere CLOSE to "consistent". None were "computerized". None had an automated system to tell the inspector what devices to look for on the particular vehicle being tested. None tested MIL operation. And I understand this topic well enough to pass the ASE tests for engine repair, performance, & electronic systems; and several Ford technical courses. Do you?

So since the OP hasn't said what state he's being tested in, your description of your state's test seems irrelevant.

sdmartin65

The electronic obd2 testing is a standard procedure as is the mil light check portion of the test. You are just painful steve83!